This chapter comprehensively examines Catha edulis (khat) and its specific effects on periodontal and peri-implant health. Khat, a plant native to East Africa and the Arabian Peninsula, contains psychoactive alkaloids including cathinone and cathine that produce stimulant effects when chewed. Despite its deep cultural roots across several societies, khat consumption poses significant periodontal health risks. This chapter explores khat’s botanical characteristics, chemical composition, pharmacological mechanisms, and pathophysiological effects specifically on periodontal and peri-implant tissues. Evidence demonstrates that chronic khat use is strongly associated with periodontal manifestations, including gingival recession, attachment loss, and alveolar bone destruction. The mechanical trauma from prolonged chewing sessions and the chemical effects of khat’s constituents create a complex environment that significantly compromises periodontal health. Particular attention is given to khat’s impact on dental implant treatment outcomes, where the plant’s vasoconstrictive properties and influence on bone metabolism may compromise osseointegration and long-term implant stability. While khat use is associated with other oral manifestations, including tooth staining, xerostomia, oral mucosal lesions, and potential cancer risk, this chapter focuses on the periodontal and peri-implant implications. This chapter provides dental practitioners with evidence-based guidance for managing the periodontal health of khat-using populations while acknowledging the complex socio-cultural context surrounding its use.